Son, wife or daughter producing blade (5)
I believe the answer is:
sword
'blade' is the definition.
(I know that blade can be written as sword)
'son wife or daughter' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'wife' becomes 'w'.
'daughter' becomes 'd' (genealogical abbreviation).
's'+'w'+'or'+'d'='SWORD'
'producing' acts as a link.
(Other definitions for sword that I've seen before include "Fencer's weapon" , "Two-edged weapon" , "Cutting weapon" , "Foil" , "Sharp weapon" .)